In traumatically injured patients, hemorrhagic patients, and surgery patients, it is known that large quantities of blood should preferably be administered in a short time at body temperature. Inasmuch as whole blood is normally stored at lower temperatures such as 4.degree. C., it is difficult to warm such blood in sufficient quantities as required. In one prior method, blood is dripped into patients by gravity and forced by pressure through blood warming coils placed in a reservoir of water warmed with a heating element. In this technique, the infusion rate is not greater than 25 ml/min. This method requires about 30 minutes to administer a single unit of whole blood.
In another method that has been proposed, microwave heaters are provided which may cause red cell destruction. Efforts to increase the rate of heating in the method of warming through coils also causes red cell destruction and possible rupture of the coils.
In accordance with the invention, the method and apparatus for administering large quantities of blood which has been stored at less than ambient temperatures continuously and rapidly to a patient at physiologically acceptable temperatures and pressures in a short time comprises directing blood through a plurality of discrete capillary paths in heat-exchange relationship with a warming medium, the number of said paths being such that the pressure of the blood is not substantially increased, and the blood is rapidly administered directly to a patient.